Dynamo-electric apparatus.



No. 821,837. PATENTED MAY 29, 1906.

W. STANLEY.

DYNAMO ELECTRIC APPARATUS. APPLICATION FILED MAY25, 1905.

Fig/J.

% tigmegrs VVlLLlAM STANLEY,' OF GREAT BAR-RINGTON, MASSACHUSETTS.

DYNAMO EL ECTRIC APPARATUS.

Specification of Letters Patent.

-Applicati011 filed May 25.1905. Serial No. 262,225.

To ailwhmrz, may concern:-

' Be it known that I, WILLIAM STANLEY, a citizen of the United States, residing at Great Barrington, Berkshire county, Massachusetts, have invented certain new anduseful Improvements in Dynamo-Electric Apparatus, of which the following is a full, clear, and exact description.

7*, My invention relates to improvements in IO oynamo-electrlc apparatus, and has for its object to provide means for generating alternating currents of a desired potential gradient.

The purpose of my invention is to produce ['5 an alternator energized by alternating currents which will give a substantially constant potential for all loads. This is brought about in the particular embodiment hereinafter described by the use of two generating elements,which when energized by constantpotential currents have opposite normal po tential gradients when supplying unity power factor currents. By normalpotential gradient? 1 mean the potential gradient which 25 an elementwill have when energized by constant-potential currents. The potential gradients of these two elements can be combined so as to neutralize each other and produce a resultant potential gradient. The resultant ,0 potential gradient existing when the altern'ator is'magnetized at constant potential I termthe' normal resultantpotential gradient. The two elements described each have a negative potential gradient when'sup- 5'plying lagging currents, producing when combined a negative normal resultant potential gradientyso that by the use of an eXciter which-has a complementaryor positive potential gradient when the-alternator is sup- 40 plying lagging currents a constant potential can also be obtained from the alternator under these conditions. 1

' The following'is a description of-an apparatus embodying my invention, reference being had to the accompanying drawings, in

which' Y 1 Figure 1 is an elevation of an alternator, partly in section.- Fig; 1 is a partial lefthand side elevation of the apparatus of Fig.

1. Fig. 1 is agpartial right-hand side elevation of said apparatus. Fig. 2 is a diagram of the stator-circuits. Fig. 3 1s a diagram of the rotor-clrcu ts.

is an exciter supplying low-frequency alter-- nating currents having a potential gradient substantially complementary to the normal result ant potential gradient of the two gen eratin elements when acting conjointly.

In t e particular embodiment shown the stators A A are the induced members and have similar windings a a wound to have the same number of poles as their respective rotors. The rotors B B are the field structures and differ from each other, in that one is wound so as to have a different number of poles from the other. Thus, for instance, the winding 5 of the'rotor B may be considered to form ten poles, while the winding 1) of the rotor B forms twelve poles. The windings on both rotor structures are multiphase and are supplied with alternating currents from the. exciter D, producing magnetic fields rotating relatively to the rotor or field structure at diiferent polar speeds.

The windings b and b are reversedrelatively to each other, so that the fields producedby them rotate in opposite directions relativelyto one another, as shown by the dottedarrows. (See Fig. 3.) Thus if the direction of rotation of the rotor is clockwise, asshown by the full arrows, (see Fig. 3,) the winding 1), forming ten poles, will produce a field rotating magnetically clockwise or in ratenteq May 29, 1906. Y

B B are two ro-v the same direction relatively to the rotor,

and the winding b, forming twelve poles, will produce a field rotating counter-clockwise ori'n the opposite direction relatively to the rotor. Such clockwise and counter-clockwise electromagnetic rotation of the fields A each statorwould be ;fiftyfivejperiods, for if t the excitation were by continuous currents the periodicity of the current fromthe stator A would be 50, while the periodicity of the current from the stator A would b =60. When,however,five-period alternating exciting-currents are employed, the rotatingfields of B produced by the exciting-currents travel faster than the rotor by five periods, and therefore increase the periodicity of the currents furnished by A, while th e fields of B reduce by five periods the periodic ity of the currents furnished by A, so that the periodicity of the current furnished both A and A will be the same, or fifty-five. Now the elementA B is operating below. synchronism, and therefore its normal potential gradient is negative, while the elementA B is operating above synchronism, and therefore its normal potential gradient is positive. If,-therefore, the windings a a of the twostator elements are connected in section, as shown in Fig. 2, the two gradients will neutralize'one another to a greater or less extent according to their several'characteristics and by proper propor tionment can be made to neutralize each other entirely.

In case lagging. loads are supplied byrthe alternator the normal potential gradients of both elements will be negative, producing a negative normal resultant potential gradient, and under these conditions the excitershould have a positive potential gradientlif the alternator is. to supply constant-potential .cur. rents-that is, the potential gradient of the eXci-ter should be complementary to the normal resultant potentialgradient. By. reason of the reaction of the alternator element under such conditions with proper proportiom ing the exciter can be made to! have such a positive potential gradient and to automatically neutralize the tendency of the alternator potential to fall under such conditions.

Energy-currents in the work-circuit tend to cause superimposed currents to flow in the rotorcircuits, which are opposite or substantially one hundred and eighty degrees apart. If, therefore, the rotors are so connected in parallel to the exciter, as. shown in Fig. 3, the exciter will be called upon to ,deliver to the machine magnetizing-currents only when the machine is delivering power factor unity load.

W hen the'machines are delivering. lagging currents, however, the supernnposed rotorcurrents are not one hundred and eightvdegrees apart in phase or opposite to each other, but coincide in phase. Such superimposed currents will therefore flow through the 6X- citing-circuit. Under these conditions, then, the characteristic of the alternator when excited by constant potential would be that of substantially constant potential when delivering power factor unity load, the normal reany load, the eXciter should therefore be constructed to give an increasing potential when the alternator is furnishing lagging currents and substantially constant potential when they are furnishing power factor unity currents.

The windings shown in the diagrams are three-phase. The invention is obviously not limited to the use of such windings or to the particular relations or proportions mentioned, since it can also be carried out by other mul- ,tiphase windings, so long as the inducing fields rotate magnetically in ,different directions and the periodicities of the induced electromotive forces are the same.

I What I claim is 1. In a system for generating electric currents, the combination of two generating elements having opposite normal potential gradients and common supply-mains leading Itherefrom.

2. In a system for generating alternating currents, the combination of two generating elements each consisting of afield-producing Winding and an induced winding, an alternetting-current exciter supplying. currents to said field-producing windings such as to setup poles revolving magnetically inopposite directions, common mains connected to said induc edv windings, and rneans for producing mechanical motion between said-field-producing and said induced windings, thewindings being such thatv the periodicities of said induced windings are equal.

3. In an alternator, the combination of a pair of statorsand a'pair of rotors, multiphase windings uponone of said pairs,.forming unequal numbers of poles, circuits for supplying alternating currents to said multiphase windings suchas to produce fields rotating in opposite directions, induced windi'ngs upon the otherof said pairs,,and means for revolving therotors at a rate such that the periodicities of the electromotive forcesgenerat edin the induced windings shall be equal. 4. In an alternator, the combination of two stators and two rotors, said rotorsbeing each provided with multiphase windings, one of said windings producing a larger number of poles than the other, the poles produced by the two windingsrotating magnetically in opposite directions, means for supplying alternating currents to said windings, and means for rotating said rotors so that the periodicities of the stators shall be the same.

WILLIAM STANLEY.

IIO

It is hereby certified that in Letters Patent No. 821,837, granted May 29, 1906, upon the application of William Stanley, of Great Barrington, Massachusetts, for an improvement in Dynamo-Electric Apparatus, an error appears in the printed specification requiring correetion, as follows: Page 2, line 23, the Word section should read series; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the ease in the Patent Office.

Signed and sealed this 19th day of June, A. D., 1906. v

F. I. ALLEN,

Commissioner of Patents.

[SEAL] It is hereby certified that in Letters Patent No. 821,837, granted May 29, 1906, upon the application of William Stanley, of Great Barrington, Massachusetts, for an improvement in Dynamo-Electric Apparatus, an error appears in the printed specification reqniring correction, as follows: Page 2, line 23, the word section should read series and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 19th day of June, A. D., 1906.

[SEAL] F. I. ALLEN,

Commissioner of Patents. 

